While one of the most obvious advantages of mass storage device lies in the portability, I discovered the biggest disadvantage of it is – the relatively long responding time.
Comparison of main memory and mass storage:
Based on this, plenty of users put forward the question – if the mass storage device which includes their valuable data is damaged somehow, is it possible for them to complete mass storage device data recovery without others’ help.
To be honest, there’s no specific answer to such kind of question. Whether successful data recovery can be done or not largely depends on the damage degree of device and what you have done to that device after data loss happened.
Here are my suggestions:
Now, let’s turn our attention to the data recovery from two mainstream mass storage devices – magnetic disk and optical disk.
Considering that hard drive is the most important and commonest storage device, I’d like to share my suggestions on hard drive data recovery first.
If you’re one of the users who’re asking questions like this – can you recover data from a bad hard drive (such as a clicking hard drive); the following content will be helpful.
First of all, you should determine which type of damage this hard drive is suffering from.
Here’s how to do:
If you have accidentally formatted your USB mass storage device like USB flash drive, you must be wondering how to get back the data you need.
Well, how can you recover USB mass storage device? The answer is simple: just use MiniTool Power Data Recovery, which has been used and praised by large numbers of computer users.
Please complete those operations to recover data from a USB flash drive (here, I take accidental formatting as an example).
When all checked files are recovered to appointed path, a prompt will appear in the software, suggesting that you can close the software to end the work of recovering data from USB mass storage device.
Are you stuck in the situation when your data are accidentally deleted from optical drive, but you can’t find a suitable recovery tool to regain them? If your answer is positive, I can help you with that.
There are 4 steps to recover data from a CD/DVD.
You should wait patiently for the completion of optical drive data recovery.
Don’t worry when CD/DVD is corrupted or scratched since Power Data Recovery could also be helpful.>
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In this section, I’ll show you the structure of magnetic disk in order to lay foundation on magnetic disk recovery. So, users who have seen this will not ask questions like can you recover data from a bad hard drive or not. Then, I’ll tell you how to define a good magnetic disk by looking at 4 main parameters.
According to statistics, magnetic disk is the most common form of mass storage device used currently. Magnetic disk is often provided with thin rotating platter (platters), which is (are) used to save data, a magnetic head, which is used to read data and a actuator arm, which is used to help magnetic head locate the accurate location of certain data.
The magnetic read and write head is positioned above or below platter so that it will rotate along with the platter and its rotational locus forms lots of concentric circles, which are what people called magnetic tracks. The position of read and write head is changing by the actuator arm, so you can read data from different concentric tracks.
Information is often stored on magnetic disk in the unit of block and one information block can contain either just one sector or multiple sectors. The length of access information block, platter number, track number and sector number should all be given when information is exchanging between magnetic disk and main memory. In fact, these parameters form the actual “Address” to access disk memory.
To tell the truth, performance of disk storage system is mainly measured by the following 4 parameters: recording density, storage capacity, addressing time and data transfer rate.
One: recording density.
Recording density is also known as storage density and it is usually represented by track density plus bit density. It refers to the number of tracks per unit length along the radial direction of the disk; the unit of track density is tracks per inch (TPI). Bit density refers to the number of bits per unit length along the track direction; the unit of it is bits per inch (BPI).
Two: storage capacity.
Storage capacity of magnetic disk actually refers to the amount of useful information that can be stored on the disk; the storage capacity is represented in the unit of byte and it can be calculated through this formula: C=n*K*S*b.
Three: addressing time.
The addressing time refers to the time which is needed for the magnetic head to reach the required read/write position from the start position.
It includes two parts:
Since the time needed by magnetic head to wait different sectors to reach the specified position is different, so you generally take half of the time used by platter to rotate a circle as the average latency. As a result, the average latency is obviously related to the rotational speed of disk, while seek time is determined by the disk performance, which largely depends on the disk manufacturer.
Four: data transfer rate.
Data transfer rate refers to the number of bytes read or written by head per second after it found the correct address. Magnetic disks are divided into hard disk and floppy disk according to different storage media.
Hard disk vs. floppy disk:
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Optical disk is also a common storage medium you can see easily in daily life; it reads and writes information by taking advantage of optical and electrical principle. Being made of reflective material, the optical disk often stores data through making some changes on the surface.
When the optical disk is rotating, the laser beam will irradiate the reflective surface with information stored on. In this way, data can be recognized and read according to changes in the strength of reflected light.
Data is stored on optical disk in single spiral track and this is totally different from tracks on magnetic disks. The spiral track stretches from the inside to the outside of the disk and it is also divided into different sectors, just like in magnetic disk, and the capacity of each sector is 2KB.
CD-ROM is also known as Compact Disk-Read Only Memory; its platter has already contained programs and data which had been written by the manufacturer in advance. Therefore, you can only read data from it, having no right to modify the data or write new data into it.
This kind of optical disk is also called Compact Disk-Write Once Read Many; you can write data into its platter for one time. Once information is written into a CD-WORM, it will be kept there permanently until the disk is broken. You can read those data as many times as you want, but you still have no right to modify them or add new data.
CD-RW stands for Compact Disk-ReWritable; this kind of optical disk is similar to magnetic disk because it can be read and written repeatedly. The data writing and reading principle varies with the different materials used to make disk.
All in all, I want to say the mass storage device data recovery is feasible, though the possibility of it large depends on the degree and type of disk damage and the things you do after data loss.
You should take actions immediately to recover data and stop using the device at once so as to avoid secondary damage.